Discharge for concrete mixers



Nov. 8, 1938. E. H. LICHTENBERG E-r AL 2,135,874

DISCHARGE FOR CONCRETE MIXER Filed May 1, 1935 Patented Nov. 8, 1938UNITED STATES was? FFlCE DISCHARGE FOR CONCRETE ivnxsns Application May1, 1935, Serial No. 19,282

3 Claims.

This invention embodies certain improvements in concrete mixing machinesof the type utilizing a rotating drum for the agitation of the aggregatematerials, and a discharge chute dis- 5 posed operatively at thedischarge opening of the drum and movable to positions wherein itprevents or effects the discharging action from the said agitatingreceptacle. To those versed in the art of these mixing machines it isknown that the discharging operation of a machine of this general typereferred to involves an elevating of the material from the lower portionof the drum to the upper portion by certain socalled pick-up buckets,which, in association with certain throw-over blades, produce thenecessary agitation to mix the various aggregates handled in themachine. The discharge chutes heretofore employed have been designed soas to be mounted at the discharge opening of the drum,

and the chute is movable from what may be termed its non-dischargingposition, to a discharging position wherein one end of the chute isdisposed near the upper interior portion of the drum in such a positionthat the aggregates being agitated and elevated are caused to bedeposited in the upper end of the chute and to flow downwardly from thechute to a point external to the drum.

In previous discharge chute mechanisms, such as above described, thenatural line of flow of the concrete aggregates as they are raised andpass from the pick-up buckets is curved in the direction of the rotationof the drum. That is to say, as the aggregates are elevated by thepick-up buckets at a certain point in the elevation, they flow from thepick-up buckets by gravity and inertia imparted thereto incident to therotation of the drum, along a curved flow line. A certain portion of theaggregates under these conditions will pass into the upper portion ofthe chute when the latter is in its discharging position, and will thuspass out of the drum. However, on account of the disposition of theinclined discharge chute, when in discharging position, at an abruptangle to the direction of flow of the aggregates passing thereto fromthe pickup buckets, the action of the chute, according to arrangementsprior to this invention, has been 50 to somewhat abruptly interrupt thedirection of flow of the aggregates to carry them in the direction ofthe inclination of the chute, giving rise to certain disadvantages. Inthe 'first place, this interruption of the direction of the flow in 55an abrupt manner has a certain tendency to segregate the aggregates whenthey are impinged against the wall of the chute as they take the outwardflow in a new direction for discharging from the receptacle. Again, aVery considerable abrasive action of the aggregates incident to suchimpingement is produced against the chute wall or'walls, therebycreating wear which in time necessitates the replacement of the chute.

In the carrying out of this invention, the particular object in View hasbeen to provide a 10 mounting for the discharge chute such that it isgiven an inclination, when in discharging position, which inclinationcorresponds with the inclination, so to speak, of the curved line offlow of the aggregate materials as they pass from the 15 pick-up bucketsonto the chute in the discharging operation.

It has been found, by the coordination of the direction of inclinationof the chute in its discharge position with the natural curved flow line20 of the aggregates passing from the pick-up buckets thereonto, thatthe disadvantages previously referred to are avoided, and, in additionto this result, it has been found that an increase in the speed ofdischarge owing to the elimination of momentary stoppage of the movementof the aggregates necessary when they change their angle of flow onentering the discharge chute, is produced. 30

In the accompanying drawing the present invention is shown according toone embodiment thereof adapted to the construction of a mixing machinewherein the discharge chute is of the type which is pivotally mountedadjacent to the discharge opening of the mixing drum so as to be shiftedfrom a position wherein the body of the chute is arranged almostentirely external to the drum for nondischarging action, and is shiftedpivotally so as to carry practically the entire 40 body of the chuteinto the drum to a position for receiving the aggregates from thepick-up buckets when the discharging action is desired. However, it isnot desired to be limited to this particular type of discharge chutemechanism, for 45 the principles of the invention may be adapted toother discharge chute constructions, within the purview thereof.

In the accompanying drawing Figure 1 is a side elevation of a mixingmachine embodying a construction of discharge means made according tothe invention.

Figure 2 is an end View looking toward the discharge end of the machineand illustrating the peculiar angularity of the mounting of thedischarge chute itself, the same being illustrated as when operative fordischarging purposes.

Figure 3 is a fragmentary perspective view looking toward the dischargeend of the 'machine, and showing the discharge chute as disposed in anon-discharging position.

Figure 4 is a fragmentary, somewhat diagrammatic view, partly brokenaway and partly shown in section, of the drum, illustrating the movableand stationary discharge chute devices as when the movable chute isperforming its discharging function by receiving the mixing aggregatesfrom the pick-up buckets carried by the interior walls of the drum.

Referring to the drawing and describing the invention in detail, it isnotable that the mixing machine illustrated comprises certainconventional parts including a frame I, the charging hopper 2, the drum3, the movable discharge chute 4, and the stationary discharge chute 5.The drum is supported by suitable rollers and is driven by drive pinions6 carried by a suitable motor driven shaft 1, the said pinions engagingone .or more annular gears or gear rings surrounding the drum. The drivepinions and gears are not shown in detail in the drawing, but the motorfor actuation of the shaft 1 is-denoted 8. A water tank 9 supplies waterto the drum in the customary way through a suitable water pipe Ill.

Referring now to the discharge mechanism, involving particularly thechutes 4 and 5, it is noted that the chute 5 is stationary and mountedbetween certain uprights of the frame I in any suitable and substantialmanner. The upper end of the stationary chute 5 terminates adjacent tothe discharge opening of the drum which is located at the side thereofopposite to that at which the charging hopper 2 is mounted. The movabledischarge chute 4 is disposed above the discharge chute 5 and inpractical use may constitute a continuation of the chute 5 when thechute 4 is disposed in discharging position. The chute 4 is directlycarried by brackets ll secured to and movable with an actuating shaft l2which is supported in suitable bearing brackets carried by the parts ofthe frame I at the discharge end of the machine. One of these parts ofthe frame is an inclined brace or supporting member Ia, seen best inFigure 2, said member Ia supporting the upper end of the said inclinedactuating shaft l2.

By oscillation of the shaft l2 the discharge chute 4 carried thereby maybe shifted from a position such as shown in Figure 3, wherein it isinoperative and practically withdrawn from the drum 3, to the positionillustrated by the inner dotted lines of Figure 1, wherein the saiddischarge chute has its lower or outer end just above the inner or upperend of the chute 5, and its upper end projecting inwardly into the drumand upwardly to a point somewhat but not greatly spaced from the path ofmovement in which the pick-up buckets 13 of the drum operate. In theinward operative position of the chute 4, wherein it performs itsdischarge function, the upper end of the chute receives the mixedaggregates elevated by the pick-up buckets l3, and said aggregates flowdown the chute 4 onto the chute 5 and thus out of the drum to anysuitable receptacle or point of deposit.

The means with which to actuate the shaft 12 are not essential ormaterial to the invention. This shaft could be shifted to assume its twopositions described, in small machines, by a manual handle carried bythe shaft -or connected therewith. But in larger machines,'such asillustrated in the drawing, it is contemplated to operate the shaft I 2by means of a curved rocker arm H attached to one end thereof andconnected by an actuating link I5 to certain power discharge mechanism,including a shaft l6 having a crank I! directly attached to the lowerend of the link l5. This power discharge mechanism may involvealternative manual control means, but, since these manual and poweroperated devices are not essential features of the invention, they arenot further described. Such mechanisms are common in the mixing machineart today and will be fully understood'without detailed showing anddescription by persons acquainted with such machines.

The important feature of the invention lies in the disposing of thechute 4 in the manner seen in Figure 2, namely, so that when the chuteis in its discharging position, it inclines not only toward the chargingend of the drum, but is disposed at .an inclination to a vertical lineintersecting the axis of the drum when viewed from the discharging endof the machine. The last mentioned inclination is one corresponding indirection with the curved line of flow of the aggregates mixed in thedrum as these aggregates pass from the pick-up buckets when the latterreach their uppermost positions at which the aggregates must shift fromthe said buckets incident to the gravitative action of the aggregatesand the inertia imparted thereto by the rotation of the drum. It will,therefore, be seen that the longitudinal axis of the chute 4 isangularly disposed with respect to the horizontal and vertical planes ofthe longitudinal axis of the mixing drum 3.

Figure 4 of the drawing illustrates in a somewhat diagrammatic mannerthe manner in which the inclination of the chute 4 corresponds with themore or less inclined path of movement of the aggregates as they passfrom the pick-up buckets to the chute, this path being a curved flowline, practically speaking, of which curved flow line the line ofinclination of the chute 4 is intended to be a continuation.

Since the aggregates in passing from the buckets l3 to the chute 4 arenot required to be abruptly stopped and shifted with a direction of flowat an abrupt angle to the natural flow line thereof when leaving thepick-up buckets, the speed with which the aggregates may pass onto andalong the chute 4, and out of the machine, is increased as compared withthe prior types of discharge devices. Likewise, as previously suggested,the impact of the aggregates against the chute 4 is substantially inline with the longitudinal axis of the chute and thereby a materialreduction in the abrasive action of these aggregates upon the chute isobtained. The speed of discharge of the aggregates is highly desirablein these machines because the factor of the time of discharge is one ofthe several controlling factors that determines the efliclency of theentire mixing machine in its operation. The speedier the discharge,therefore, the more mixing operations may be performed in a given timeof daily or other use of the mixing machine. Again, the avoidance of therequirement of replacing the discharge chute because of the abrasivewear caused by the aggregates thereon atfords a saving of expense andavoids loss of time in making the replacement, giving rise to essentialadvantages in the use of the discharge mechanism of the invention.

Having thus described our invention, what we claim as new and desire tosecure by Letters Patent of the United States, is-

l. A mixing machine of the character described, comprising, incombination, a mixing drum, parts within said drum for agitating andelevating aggregate materials within said drum, a discharge chutemovable to discharging and non-discharging positions extending into saiddrum, and means for pivotally mounting said chute with respect to saiddrum, including an axis member angularly disposed with respect to thehorizontal plane of the longitudinal axis of the drum, whereby uponmovement of said chute to discharging position aggregate materialswithin the drum elevated by said parts are transferred to said chute anddischarged from the drum substantially in their direction of flow fromsaid parts.

2. A mixing machine of the character described, comprising, incombination, a mixing drum, parts within said drum for agitating andelevating aggregate materials within said drum, a discharge chutemovable to discharging and non-discharging position extending into saiddrum, means for pivotally mounting said chute with respect to said drumincluding an axis member angularly disposed with respect to thehorizontal plane of the longitudinal axis of the drum, andinstrumentalities for pivotally moving said chute about said axis memberto discharging or non-discharging positions, whereby upon movement ofsaid chute to discharging position aggregate materials within the drumelevated by said parts are transferred to said chute and discharged fromthe drum substantially in their direction of flow from said parts.

3. An apparatus of the character described, comprising, in combination,a mixing drum, means within said drum for agitating and elevatingaggregate materials within the same, a discharge chute associated withthe drum and movable to discharging and non-discharging positions, andinstrumentalities for movably mounting said chute with respect to saiddrum and including a shaft and bearing members for said shaft, the shaftand bearing members being disposed with their longitudinal axes at anangle with respect to the horizontal plane of the longitudinal axis ofthe drum, whereby upon movement of the chute to discharging positionaggregate materials within the drum elevated by said means aretransferred to said chute and discharged from the drum substantially inthe direction of flow from said agitating and elevating means.

ERICH H. LICH'IENBERG. OSCAR SHECK.

